"Food Standards Scotland welcomes initiatives for reducing food waste, but we wouldn’t advise consumers to use the ‘sniff test’ as a general rule for all foods. You can’t see or smell the bugs that can cause food poisoning and storage can affect the safety of some foods more than others.
To control these risks, food businesses must apply the appropriate date labels to their products based on the scientific evidence for their safety and shelf life. That’s why we would always encourage you to look at the label for information on how to store products and for how long.
The ‘use by date’ is the most important storage instruction to look out for as it means the food can be used until the end of this date but not after.
Manufacturers apply these to perishable foods that can go off quickly to ensure they are eaten before any harmful bugs that may be present are able to grow to levels that can cause illness.
Foods that don’t have a ‘use by’ date are usually labelled ‘best before’, which means that they will be safe to eat after this date but may not be at their best, for example they have lost flavour or gone a bit stale.
For ‘best before’ foods, it should be safe to use smell or appearance to decide if you want to eat them, but always look at the label first to make sure.”